<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Test Window</title>
    <style>
        body {
            font-family: system-ui, -apple-system, sans-serif;
            padding: 20px;
        }
    </style>
</head>
<body>
    <h2>Test Window Created!</h2>
    <p>This window should appear and auto-close.</p>
</body>
</html>